Synthesis of new benzothiazole derivatives bearing thiadiazole as monoamine oxidase inhibitors

Monoamine oxidases (MAO) are enzymes that catalyze the oxidative deamination of monoamines such as dopamine, noradrenaline, adrenaline, and serotonin. Recent studies have shown that numerous benzothiazole derivatives exhibit hMAO inhibitory activity in the micromolar concentration range. In this study, a novel series of benzothiazole-thiadiazole (5a-5l ) was synthesized and characterized their chemical structures by ¹H-NMR, ¹³C-NMR, and Mass spectroscopy. These compounds were evaluated as inhibitors for types A and B MAO enzymes. Compounds 5f and 5l were the most active derivatives in the series with an IC₅₀ values of 0.107 ± 0.003 and 0.128 ± 0.004, respectively. Furthermore, cytotoxicity of compounds 5f and 5l were investigated and found as non-cytotoxic.     

Synthesis and evaluation of iodinated benzamide derivatives as selective and reversible monoamine oxidase B inhibitors.

A new series of iodinated analogues of N-(2-aminoethyl)benzamide was synthesized and evaluated for inhibitory potency and specificity toward monoamine oxidase type-B (MAO-B). Among them, N-(2-aminoethyl)-2-chloro-4-iodobenzamide hydrochloride (2d) showed high inhibitory potency and selectivity against MAO-B. The type of MAO-B inhibition by 2d was non-competitive and the inhibition constant (Ki) was 0.80 microM. Strong and selective in vivo MAO-B inhibition by 2d was also confirmed. The brain MAO-B inhibition by 2d was reversible and the enzyme activity completely returned to the control value 24 h after administration. Compound 2d was, therefore, considered to be a candidate for advanced development as a radioiodinated ligand that may be useful for functional MAO-B studies in the living brain using single photon emission computer tomography.     

Synthesis of some novel pyrazoline‐thiazole hybrids and their antimicrobial activities

A series of novel thiazolyl pyrazolines 7a‐h , 9a‐f , and 11a‐f have been synthesized by the reaction of thioamide derivatives 5a , b with 1‐aryl‐2‐bromoethanones 6a‐d , chloroacetones 8a‐c , and hydrazonoyl chlorides 10a‐c . Additionally, pyrazoles 15a‐c and 20 were prepared starting from enaminone 13 . These newly synthesized compounds were screened for their in vitro antibacterial activity against four bacterial species. Compound 11b showed a moderate activity against Klebsiella pneumoniae. Compounds 7c and 11c revealed a moderate activity against Pseudomonas aeruginosa. In addition, the antifungal activity of the newly synthesized compounds was determined against five fungal strains. Compounds 7e , 7g , and 11e showed a good activity against Aspergillus flavus and Penicillium expansum.     

Synthesis of new pyrazolone-based heterocycles as inhibitors of monoamine oxidase enzymes

A series of new substituted pyrazoles embedded with a variety of function groups has been synthesized from 4-[4-(1,2-dihydro-2,3-dimethyl-1-phenyl-5-oxo-3H-pyrazol-4-yl)]-2-cyano-4-oxo-butanenitrile (4). The synthesized compounds were fully characterized and their structures were elucidated based on elemental analysis, spectral data, and alternative synthetic pathways, whenever possible. The pharmacological activities of these new compounds as inhibitors for of type A and type B monoamine oxidase (MAO) enzymes have been investigated and compared to the most common inhibitors of MAO enzymes used to treat depression and anxiety such as deprenyl (selegiline), moclobemide, and clorgyline drugs. The most potent of the synthesized compounds was 4, 11, and 53 which showed higher inhibition activity toward type A MAO enzyme and even exceeded that of deprenyl, moclobemide, and clorgyline drugs.     

Synthesis and monoamine oxidase A/B inhibitory evaluation of new benzothiazole-thiazolylhydrazine derivatives

Abstract

In this study, a novel series of benzothiazole-thiazolylhydrazine (3a–3i) was synthesized and their structures were characterized by ¹H-NMR, ¹³C-NMR spectrometry, and mass spectroscopy. These compounds were evaluated as inhibitors of type A and type B monoamine oxidase (MAO) enzymes. The most active compound 3b (2-((2-(2-(4-(4-Nitrophenyl)thiazol-2-yl)hydrazineylidene)-2-phenylethyl)thio)benzothiazole) showed strong inhibitory activity at hMAO-A (IC₅₀ of 0.095?±?0.004?µM). Furthermore, compound 3i (2-((2-(2-(4-(2,4-dichlorophenyl)thiazol-2-yl)hydrazineylidene)-2-phenylethyl)thio)benzothiazole) showed significant inhibition profile on hMAO-A with the IC₅₀ values 0.141?±?0.006?µM.     

Synthesis of new uracil non‐nucleoside derivatives as potential inhibitors of HIV‐1

6‐(2‐Phenylethyl) and 6‐cyclohexyl 5‐cyanouracils ( 1a,b ) were synthesized and reacted with chloromethyl ethyl ether, benzyl chloromethyl ether, chloromethyl methyl sulfide and (2‐acetoxyethoxy)methyl bromide. New uracil analogues of (S)‐DHPA were synthesized by reaction of compounds ( 1a,b ) with ((S)‐2,2‐dimethyl‐1,3‐dioxolane‐4‐yl) alkyl p‐toluenesulfonate.     

Synthesis and antimicrobial activity evaluation of new dithiocarbamate derivatives bearing thiazole/benzothiazole rings

The synthesis of 2-(substituted phenyl)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (A1-A24) derivatives and 2-(4-substituted thiazol-2-ylamino)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (B1-B14) derivatives was undertaken starting from the potassium salt of 4-(2-pyrimidinyl)piperazine dithiocarbamate. The structures of the obtained compounds were elucidated by ¹H NMR, ¹³C NMR, MS spectral data, and elemental analysis. The antimicrobial activity of the thirty eight newly synthesized compounds were tested against 12 microorganism strains using the microdilution technique. Compounds 2-(4-ethoxycarbonylthiazol-2-ylamino)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (B12), 2-(3-fluorophenyl)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (A18) and 2-(3,4-difluorophenyl)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (A21) were determined to possess high antimicrobial activity.     

噻唑环衍生物的合成

噻唑环及其衍生物广泛存在于具有生物活性的分子中[1]可用于抗生素和消炎药的制备[2]。本文合成的几种噻唑基衍生物—类以HIV蛋白酶为靶点的新型抗艾滋病药物利托那韦的重要中间体[3-5],对其合成工艺的研究具有较实际的意义。噻唑环衍生物可通过α-卤代羰基化合物与硫代酰胺缩合而成[6],α-巯基酮与腈缩合反应得到,也可采用醛与半胱氨酸缩合,再与二氧化锰作用得噻唑类化合物[7]。本文采用α-氯代羰基类化合物与硫代酰胺缩合而得三种噻唑类化合物,产率较为理想。1合成路线设计合成路线设计可表示如下图1图1目标化合物的合成路线F ig.1 The …     

Synthesis of thiazole derivatives

By condensing aldehydes of the benzothiazole series with dimethylaniline, leuco-bases of dyes of the type of Malachite Green have been synthesized. The oxidation of these bases has given new analogs of Malachite Green containing benzothiazole nuclei; the main absorption maxima of the dyes have been determined.For Communication XXIV, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1037–1039, August, 1973.     

Synthesis and biological evaluation of 5-methyl-4-phenyl thiazole derivatives as anticancer agents

Abstract

New N-(5-methyl-4-phenylthiazol-2-yl)-2-(substituted thio)acetamides were synthesized and studied for their anticancer activity. The title compounds were procured by reacting 2-chloro-N-(5-methyl-4-phenylthiazol-2-yl)acetamide with some mercapto derivatives. The structural elucidation of the compounds was performed by ¹H-NMR, ¹³C-NMR and LC-MS/MS spectral data and elemental analyses. The synthesized compounds were investigated for their antitumor activities against A549 human lung adenocarcinoma cells and NIH/3T3 mouse embryoblast cell line for determining their selective cytotoxicity. 2-[(1-methyl-1H-tetrazol-5-yl)thio]-N-(5-methyl-4-phenylthiazol-2-yl)acetamide (4c) showed high selectivity, and whose IC₅₀ value was determined as 23.30?±?0.35?µM and >1000?µM against A549 human lung adenocarcinoma cells and NIH/3T3 mouse embryoblast cell lines, respectively. 2-[(1-Methyl-1H-imidazol-2-yl)thio]-N-(5-methyl-4-phenyl thiazol-2-yl)acetamide (4a) and 2-[(1-Methyl-1H-tetrazol-5-yl)thio]-N-(5-methyl-4-phenyl thiazol-2-yl)acetamide (4c) exhibited the highest apoptosis percentage among those tested, but not as high as the standard, cisplatin.     

Synthesis of new indoyl-1,3,4-oxadiazole and oxadiazine derivatives. Potential monoamine oxidase inhibitor activity

New indolyl-1,3,4-oxadiazole and oxadiazine derivatives were prepared as reversible monoamine oxidase inhibitors. The compound 5-(3-methylindolyl)-1,3,4-oxadiazol-2(3H)one was shown to be a good monoamine oxidase B inhibitor.     

Synthesis of thiazole derivatives

5- and 6-Vinyl-2-methylbenzothiazoles were synthesized. Thiacyanine dyes with vinyl groups attached to the heterocyclic residues were obtained from the quaternary salts of the new bases. The main absorption maxima of the dyes were determined.For part XXIII, see [1].     

Synthesis and biological evaluation of triazepane derivatives as DPP-IV inhibitors

A series of triazepane derivatives such as (R)-3-amino-1-(1,2,5-triazepan-1-yl)-4-(2,4,5-trifluorophenyl)butan-1-ones (7, 13a-p) and (R)-3-amino-1-(1,2,5-triazepan-5-yl)-4-(2,4,5-trifluorophenyl)butan-1-ones (17a-e) was synthesized and evaluated for their ability to inhibit dipeptidyl peptidase IV (DPP-IV) enzyme. Compounds with the acid moiety were found to be potent inhibitors of DPP-IV without inhibiting CYP 3A4. Among them, compound 13p ((R)-4-[1-acetyl-2-{3-amino-4-(2,4,5-trifluorophenyl)butanoyl-1,2,5-triazepan-5-carbonyl}benzoic acid]) showed a good in vitro activity without inhibiting CYP.     

Synthesis and biological evaluation of thiophene derivatives as acetylcholinesterase inhibitors

A series of new thiophene derivatives has been synthesized using the Gewald protocol. The acetylcholinesterase inhibition activity was assayed according to Ellman's method using donepezil as reference. Some of the compounds were found to be more potent inhibitors than the reference. 2-(2-(4-(4-Methoxyphenyl)piperazin-1-yl)acetamido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (IIId) showed 60% inhibition, compared to only 40% inhibition by donepezil.     

Synthesis of novel flavonoid derivatives as potential HIV‐ Integrase inhibitors

Eighteen novel flavonoid derivatives ‐ substituted chalcones and flavones were synthesized and characterized by using NMR, IR, UV/Vis spectroscopy and elemental analysis. The target compounds were achieved by using a sequence of simple and effective reactions starting from phloroglucinol. The initial hydroxyl groups were protected by methylation and in the final flavones the 5‐OH group was selectively demethylated by means of AlBr₃. 5‐methoxy flavones exhibit a strong fluorescence, which was quenched after the removal of the methyl group.     

Synthesis and electroluminescent properties of fluorene‐based copolymers containing electron‐withdrawing thiazole derivatives

We synthesized two fluorene‐based copolymers poly[(2,5‐bis(4‐hexylthiophen‐2‐yl)thiazolo[5,4‐day]thiazole‐5,5′‐diyl)‐alt‐(9,9′‐dioctylfluorene‐2,7‐diyl)] ( PF‐TTZT), and poly[(5,5′‐bis(4‐hexylthiophen‐2‐yl)‐2,2′‐bithiazole‐5,5′‐diyl)‐alt‐(9,9′‐dioctylfluorene‐2,7‐diyl)] (PF‐TBTT), which contain the electron‐withdrawing moieties, thiazolothiazole, and bithiazole, respectively. Through electrochemical studies, we found that these two polymers exhibit stable reversible oxidation and reduction behaviors. Moreover, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PF‐TBTT are lower than those of PF‐TTZT, and the bandgap of PF‐TBTT is smaller than that of PF‐TTZT. Thus the bithiazole moiety in PF‐TBTT is more electron‐withdrawing than the thiazolothiazole moiety in PF‐TTZT. Light‐emitting devices with indium tin oxide (ITO)/poly(3,4‐ethylene dioxythiophene):poly(styrenesulfonate)(PEDOT)/polymer/bis(2‐methyl‐8‐quinolinato)‐4‐phenylphenolate aluminum (BAlq)/LiF/Al configurations were fabricated. The performance of the PF‐TBTT device was found to be almost three times better than that of the PF‐TTZT device, which is because electron injection from the cathode to PF‐TBTT is much easier than for PF‐TTZT. We also investigated the planarity and frontier orbitals of the electron donor‐acceptor (D‐A) moieties with computational calculations using ab initio Hartree–Fock with the split‐valence 6‐31G* basis set. These calculations show that TBTT has a more nonplanar structure than TTZT and that the bithiazole moiety is more electron‐withdrawing than thiazolothiazole. These calculations are in good agreement with the experimental results. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7148–7161, 2008     

Synthesis and evaluation of new phosphonated δ-lactam and glutarimide derivatives as angiotensin converting enzyme inhibitors

An efficient synthesis of new γ,δ-insaturated δ-lactam and glutarimide derivatives bearing a phosphonomethyl group from a common allylphosphonate precursor is described. Our approach is based on a two-step procedure involving the preparation of phosphonated-1,5-ketoester and −1,5-diester followed by an amidation–heterocyclization sequence. The first step proceeds via Michael's addition of ethyl acetoacetate and diethyl malonate on an allylphosphonate starting material. The second step consists of a base-promoted intramolecular amidation-cyclization sequence with primary amines, which accounts for the construction of δ-lactams and glutarimide skeletons. We performed the evaluation of angiotensin I-converting enzyme (ACE) inhibition using an in vitro enzyme assay on six new compounds. Five compounds showed potent ACE inhibitory activity, with IC₅₀ values ranging from 0.02 to 0.27 mg/ml. Compared with Captopril, used as a reference drug, two new glutarimide derivatives exhibited higher efficiency ACE inhibition activity.